1. Field of the Invention
The present invention relates to a magnetic disk apparatus and an information reproducing method.
2. Description of the Related Art
With rapid improvements in the recent information processing technology, a higher recording density of a recording medium on a magnetic disk apparatus and a higher speed of recording data in the medium have been strongly demanded. For example, controlling technologies for accurate positioning of the head have been developed to improve the recording density, and bit-patterned media technologies have been developed to solve a heat fluctuation problem that arises from the reduced recording bit size.
To increase the speed of recording data onto the recording medium, JP-A H10-233063 (KOKAI) suggests a technology of arranging zones having concentric or helical tracks with respect to the center of rotation in a magnetic recording medium and providing each zone with an alternative track. With this technology, even when a defective sector appears, a magnetic disk that does not require long time in accessing data can be offered.
JP-A 2007-73116 (KOKAI) discloses a technology of designing the core of the magnetic recording head to have a width larger than a track width and recording data by sliding the magnetic head by a track pitch in the track width direction to increase the recording density of a patterned medium.
The above two documents, however, do not touch upon an operation of reproducing information from recording bits by making an access to more than one track. If the width of the reproducing element of a magnetic head is greater than the width of a track, the value acquired through an access is the sum of values recorded in several recording bits. For this reason, a process needs to be executed to retrieve individual values of the recording bits from the acquired value. In an effort to realize high-speed processing of this operation, a suitable arrangement of recording bits on a magnetic disk has been a problem to be solved.